Apparatus for sensing proximity of a moving target

An apparatus for sensing the position of a moving target having an undulating surface, the apparatus comprising:

• a transmitter for transmitting a radio frequency signal from a reference point to a moving target having an undulating surface;
• a sensor responsive to the radio frequency signal reflecting from the undulating surface of the moving target for sensing a range of distances between a reference point and an undulating surface of a moving target, the sensor including:
• a detector for detecting a distance signal representative of a range of distances between a reference point and an undulating surface of a moving target,
• a maximum and minimum generator responsive to the detector for generating a maximum distance range voltage signal representative of a maximum distance range value between a reference point and an undulating surface of a moving target and for generating a minimum distance range voltage signal representative of a minimum distance range value between a reference point and an undulating surface of a moving target,
• a memory device responsive to the maximum distance range signal and the minimum distance range signal for storing the maximum and minimum distance range voltage signals during a predetermined time period,
• a range value generator responsive to the memory device for generating a range value signal having an amplitude representative of a range value between the maximum distance range value and the minimum distance range value, and
• an output signal generator responsive to the range value signal for generating an output signal when the amplitude of the range value signal exceeds a predetermined threshold.

An apparatus for sensing the proximity of a moving gear, the apparatus comprising:

• detecting means for detecting when a tooth of a moving gear is positionally aligned with a reference point and when a valley of a moving gear is positionally aligned with the reference point;
• maximum and minimum generating means responsive to the detected gear tooth and the detected gear valley for generating an electrical signal including a DC voltage level has a maximum amplitude representative of the distance between the reference point and a gear wherein the DC voltage level has a maximum amplitude when a gear tooth is positionally aligned with the reference point and wherein the DC voltage level has a minimum voltage level when the gear valley is positionally aligned with the reference point;
• storing means responsive to the maximum distance range signal and the minimum distance range signal for storing the maximum and minimum distance range DC voltage signals during a predetermined time period;
• range value generating means responsive to said storing means for generating a range value signal having a voltage level with an amplitude representative of a range value between the maximum distance range value and the minimum distance range value;
• threshold generating means responsive to said storing means for generating a threshold signal having a voltage level with amplitude corresponding to the approximate mid-point between said maximum distance range signal value and said minimum distance range signal value;
• and
• output generating means for generating an output signal having a first predetermined voltage level when the amplitude of the range value signal exceeds the amplitude of the threshold signal, and having a second predetermined voltage level when the amplitude of the first signal is less than the amplitude of the threshold signal.